The present invention relates to a pneumatic system for conveying particulate materials and more particularly to pneumatic conveying ejectors for introducing a flow of pressurized motive gas that provides energy for conveying the particulate solids.
Typically, particulate material that is stored in a hopper or silo or is exiting a manufacturing process is gravity fed into a solids supply vessel or rotary valve airlock and then conveyed through a pipeline to a remote collection site. The pipeline, which is connected to the material outlet at the bottom of the solids supply vessel or rotary valve airlock, is pressurized to within a desired pressure range that provides a pressure differential between the solids supply vessel or rotary valve airlock and the remote collection site suitable to achieve a desired material flow in the pipeline. An ejector may, under certain conditions, replace the solids supply vessel or rotary valve to supply compressed gas (e.g., air) into the pipeline to move the particulate material through the pipeline as it is delivered from the granular solids source.
In certain environments, particulate material is conveyed using a supply of compressed gas having a gauge pressure of 15 psig or less. This low pressure gas is supplied by a suitable low-pressure compressor. Alternately, rather than using a dedicated low-pressure compressor, the plant's high-pressure (e.g., 80-120 psig) compressed gas source may be used to power the conveying ejector. The high-pressure supply is regulated to a lower pressure before delivery to the ejector.